1. Field of the Invention
The present invention concerns a disconnecting apparatus intended for fitting to hydraulic circuits when it is desired to avoid pollution. It may be water, principally drinking water, or any one of various liquids used in the chemical industry.
The principle of the disconnecting apparatus is as follows.
When liquid flows in the direction which is considered normal, the disconnector allows free communication between the inflow circuits and the outflow circuits. If the direction of flow of the liquids is reversed, the disconnector automatically closes and prevents the liquid in the outflow circuit, which is considered polluted, from flowing back into the inflow circuit.
Disconnectors operating according to this principle are known. In the case of reversal of the flow, the disconnector protects the inflow circuit and discharges to the exterior the liquid coming from the outflow circuit. This is useful, for example, in the chemical industry to prevent polluted water from flowing back toward the source of clean water, in the event a valve has become defective and ceases to be watertight. In addition, if the interior space of the disconnector forms a dead zone, it must be guaranteed that there is no risk of the polluted water which is contained in this dead zone being sucked back into the inflow circuit.
2. Prior Art
Disconnecting apparatus allowing certain results to be achieved are known, but they present some disadvantages.
Certain ones are of very complicated construction. The majority present a risk. For example, even if they function adequately under normal circumstances, their design does not assure complete safety. As a result, serious incidents can occur.
The present invention has the aim of avoiding these disadvantages by achieving a disconnecting apparatus in which any operating accident gives rise to a leak visible from the exterior without however allowing any sucking back whatsoever of the polluted ouflow liquid.
In addition, the invention aims at achieving a disconnector of simple construction, using only valves and membranes of conventional type.